Vacuum tube



B. ROSENBAUM 1,765,501

VACUUM TUBE June 24, 1930 Filed Aug. 26,, 1921 INVENTOR A04 ATTORNE YS Patented June 24,

STATES BRUNO ROSENBAUM, OF BERLIN, GERMANY, ASSIGNOB TO WESTINGI-IOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA VACUUM TUBE .Application filed August 26, 1921, Serial 110 495349, and in- Germany August 18, 1917.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. I, 1313) This invention relates to electron discharge devices, and has for its object the provision of an improved construction.

It has'been found in the use of electron discharge devices commonly known as vacuum tubes, for example in radio telegraphy, that the operation is seriously impaired by vibration of the tube. This is especially so in vacuum tubes which are used for amplifiers, in which case it is necessary that there be no I disturbance when signals are not actually being received.

It has been shown by experiment that vibration of the tube causes a vibration of the electrode elements with respect to one another, and this in turn causes an audible disturbance in the telephone, receiver. If these vibrations occur in the first tube of a multistage a1nplifier,the disturbances are amplipzo fied, and are seriously objectionable in the telephones. In the usual vacuum tube there are three parts which may vibrate and cause this disturbance, namely theincandescent filament, the grid electrode, and the plate or anode electrode. 7 I

In accordance with this invention, these parts of the system are formed and arranged in such a manner that it is not possible for them to move relative to one another.

I In order to prevent vibration of the incandescent filament, it has been proposed to support the filament at several points along its length, but it has been found that these supports extract heat from the filamen and pre- 5 vent it from being uniformly heated. It has been found useless to put thefilament under a high tension, as this merely increases the frequency of vibration, as in the case of a tuned piano string. In accordance with. this invention, the filament is loosely hung between two supports, so that it is under no appreciable tension. When supported in this way it has been found that the filament will not vibrate, and will therefore produce no disturbance from this cause. The natural rigidity of the materials commonly used for lncandescent filaments, such as tungsten and Wollaston, is suflicient to prevent the filament from sagging so as to touch the adjacent electrodes.

In order to prevent vibration of the grid,

in accordance with this invention it is made extremely rigid and is firmly supported with respect to the filament. The grid is preferably in the form of a perforated cylinder concentric with the filament. It has been found that in the process of perforation the grid is increased in rigidity, and this prevents any inherent vibration. If it is desired to use a grid made of spirally wound wire, it is possible to sufficiently stiffen it by securing the turns of the spiral to a rigid support extendlng along the length of the grid. This is preferably accomplished by welding the turns of the spiral to a metallic cross connection extending parallel with the axis of the spiral.

The anode or plate may be a metallic cyl inder concentric with the filament and grid. Vibration of this element with respect to the other elements is prevented by securing it to firm supports, which may be the same supports that are used for attachment of the grid and filament.

It is in some casesof advantage to prevent relative movements of the elements and yet allow the elements as a whole to vibrate with respect to the evacuated vessel containing them. This result may be obtained by suspension of the supports for the elements from the evacuated vessel by means of flexible connections.

A preferred embodiment of the present invention is illustrated in the accompanying drawing which is described in the following paragraphs.

In this drawing there is illustrated an electron discharge device of the three-element type in which the elements are arranged and supported in accordance with this invention.

Referring now to the figure, a support 1, preferably of glass, is provided having extension arms 2 and 3. This support is secured to the portion 16 of the evacuated vessel 18 by means of the flexible membersrl'f. This construction makes it possible for the electrode support 1 to move with respect to the evacuated vessel 18.

A filament 4 is loosely hung between supports 2 and 3, and connection is made to it by means of leads 9 and 10, which may be fused into the glass support 1. A grid electrode 5, which is preferably barrel-shaped, is also supported by the glass arms 2 and 3, in this case by means of wires 14 and 15. The grid is made larger at the central portion to prevent the sagging filament from touching the grid.

Concentric with the grid and filament is the cylindrical plate electrode 8, which is also supported by the glass arms 2 and 3. By securely mounting the filament, grid and plate on the same supports, namely 2 and 3, relative motion between them is prevented.

Electrical connection to the grid and plate may be made by means of leads 11 and 13, which are fused into the glass support 1.

The foregoing construction gives thus an electrode assembly wherein the individual electrode elements constituting a triode are held together as a unit, the whole unit being free to move with respect to the enclosing vessel by reason of the yieldable resilient suspension from the vessel.

I claim:

1. An electron discharge device having a plurality of electrodes rigidly secured against motion relative to one another, and a flexibly mounted support for said electrodes.

2. An electron discharge device having a cathode filament looselyhung between two supports, a grid electrode rigidly supported with respect to said filament, and a plate electrode rigidly supported with respect to said grid and said filament.

3. An electron discharge device having a filament loosely hung between two supports, a grid electrode ri idly supported with respect to said filament, a plate electrode rigidly supported with respect to said grid and said filament, and a flexibly mounted support for said electrodes.

4. An electron discharge device comprising a fiexibly mounted dielectric support having extending arms, a filament loosely hung between said arms, and grid and plate electrodes rigidly attached to said extending arms. e

5. An electron discharge device comprising a flexibly mounted dielectric support having extending arms, a filament loosely hung between said extending arms, and grid and plate electrodes.

6. An electron discharge device comprising a flexibly mounted dielectric support having extending arms, a filament loosely hung between said extending arms, and a grid and a plate electrode concentric with said filament and rigidly attached to said extending arms.

7. An electron discharge device comprising an evacuated vessel, a support flexibly attached to said vessel having extending arms, a filament loosely hung between said extending arms, a grid electrode, and a plate electrode rigidly attached tosaid extending arms.

8. An electron discharge device comprising an evacuated vessel, a support flexibly attached to said vessel having extending arms, a filament loosely hung between said extending arms, and grid and plate electrodes.

9. An electron discharge device comprising an evacuated vessel, a support flexibly attached to said vessel having extending arms, a filament loosely hung betweensaid extending arms, and a grid and a plate electrode concentric with said filament and rigidly attached to said extending arms.

10. In an electron tube, an approximately horizontal filament, means for supporting said filament, said means permittingthe filament to sag and a tubular electrode surrounding said filament, the diameter of said electrode varying and being greatest where said sagging is greatest.

11. In an electron device, an insulating support having two pillars extending therefrom, and a plurality of concentric electrodes supported by said pillars and extending-between them at right angles to the direction in which saidpillars extend.

12. In an electron device, an insulating support having two pillars extending therefrom, and a plurality of concentric electrodes supported by said pillars and extending between them at right angles to thedirection ioo in which said pillars extend, the endsof said electrodes being rigidlyrsecured to said pillars.

13. In an electron-discharge device, an evacuated vessel, an electrode assembly comprising a plurality of electrodes held together as a unit, and means for so supporting said electrode assembly as to permit movement thereof with respect to said vessel without simultaneous motion of the individual elements thereof.

14:. In an electron-discharge device, an evacuated vessel, an electrode assembly comprising a plurality of electrodes held together as a unit, and means for yieldably supporting said electrode assembly within said vessel.

15. In an electron-discharge device, an evacuated vessel, a triode-assembly unit com-' prising cathode anode and grid elements within said vessel, and means for movably mounting said unit within said vessel.

16. In an electron-discharge device, an

evacuated vessel, a triode-assembly unit comprising co-operating cathode anode and grid elements mounted in fixed and substantially rigid relation to each other Within said vessel, and means for resiliently supporting said triode assembly in said Vessel.

17. The method of preventing vibrations of the supports of an electron tube from causing fluctuations in the output current therefrom which comprises mounting all theelectrodes thereof in rigid relation on a relative- 1y massive support and flexibly mounting said support on the electron tube. V

In testimony whereof I affix my signature.

BRUNO ROSENBAUM. 

